The present invention relates generally to thermal cooling devices, and more specifically, to a liquid cooled thermal module that is configured to be used in compact devices and that tends to mitigate any undercirculation or overcirculation of cooling fluid thereby efficiently absorbing and dissipating heat from a heat generating component.
One of the greatest challenges facing electronic technology is the effective dissipation of heat from a heat generating electronic component. As electronic components such as circuit boards and computer chips have decreased in size over the years, there has been an increased need in providing effective means for removing heat from the components. Further, many computer enthusiasts tend to overclock their computer components, which results in a large amount of heat generation. Unless the heat is effectively removed from the component, the component and the electronic system may be subject to instability and failure. Furthermore, although progress has been made in miniaturizing and improving such components, this progress has been somewhat dependent upon the thermal properties and capabilities of the component.
Heat sinks have been a common solution to the challenge of effectively dissipating heat from a heat generating electronic component. There are two fundamental considerations in designing an effective heat sink. First, a heat sink typically includes a base surface that is in substantial contact with the heat generating component in order to maximize heat conduction from the component to the heat sink. Second, the heat sink should have a large surface area in order to maximize heat transfer from the heat sink to the air via convection. In order to effectively dissipate the heat to the air, the heat sink usually includes fins. Some exemplary heat sinks are shown in FIGS. 1 and 2. As illustrated in FIG. 1, the heat sink 10 includes a base 12 and has a plurality of fins 14, such as pins, extending orthogonally from the base 12. As mentioned, the base 12 of the sink 10 provides thermal conductive contact with the heat generating component. The pins increase the overall surface area of the heat sink 10, thus enhancing the heat dissipating ability of the heat sink 10. FIG. 2 is an illustration of another heat sink 10 in which a series of spaced apart plates 16 are coupled to an orthogonally positioned with respect to as base 12. Similar to the embodiment shown in FIG. 1, the spaced apart plates 16 of the heat sink 10 in FIG. 2 serve to dissipate the heat conducted through the base 12 from the heat generating component. Other various configurations have been developed utilizing the two principle considerations discussed above.
Another important consideration when designing the heat sink is the type of material used. The heat sink should preferably be made of a material having a high thermal conductivity. Such materials include silver (429 W·m−1·K−1), copper (386 W·m−1·K−1), and aluminum (237 W·m−1·K−1). These materials are commonly used because they have relatively high thermal conductivities and they are readily available.
Although such heat sinks have enhanced the ability of a heat generating component to dissipate heat, other modifications to these heat sinks have been performed in order to further increase their capabilities. For example, one important development has been the practice of forced convection. This entails forcing air or other gases or fluids through the pins or spaced apart plates of the heat sink. Such methods of forced convection include the use of fans to circulate air in between the pins or spaced apart plates.
More recently, forced convection has been performed by circulating liquids such as water over the fins of the heat sink. A water-cooled thermal apparatus 18, as illustrated in FIG. 3, includes not only a heat sink 10 component with fins 14, but also includes a container 20 that fits over the heat sink 10. The container 20 includes an input port 22 and an output port 24 wherethrough a liquid may pass as, as well as input and output connectors 26, 28. The container 20 and the input and output ports 22, 24 include gasket seals 30 that create the water-tight seal due to the applied pressure of a mounting bracket 32 that fastens the apparatus to a circuit board utilizing fasteners 34. When the liquid is injected into the container 20, it absorbs the heat from the heat sink 10 and exits through the output port 24. This water cooled thermal apparatus 18, although effective, is bulky and may only be used in non-congested spaces where there is plenty of room for such a bulky apparatus. However, these water cooled thermal apparatuses 18 have several drawbacks.
Some of the limitations and drawbacks of the current water cooled thermal apparatuses include the inability to fit such apparatuses into compact computer configurations. Due to its size, the cooling system illustrated in FIG. 3 may only be used on a heat-generating component if there is sufficient space around the component within a case wherein the component is housed. For a desktop computer, more space is available and the water cooled thermal apparatus 18 of FIG. 3 can usually be accommodated. However, the integration of several circuit boards, graphic cards, or other electronic components within the desktop computer sometimes occupies more space within the case, thus making the installation of a water cooled thermal apparatus impossible. Further, because space is already so limited in a laptop computer, water cooled thermal apparatuses, such as that illustrated in FIG. 3, are too large and bulky.
In addition, as shown in FIG. 3, current water cooled thermal apparatuses 18 are not effectively designed to maximize the amount of heat transfer to a given volume of water as it passes through the apparatus. Instead, the water is simply injected into the apparatus from the input port 22 that is orthogonally disposed relative to the base 12. Upon entering, the water impinges upon the fins 14 of the base 12 and is disseminated in a random fashion therethrough. As understood, there is no apparent circulation path from the input port 22 to the output port 24. Instead, the output port 24 is also disposed orthogonally relative to the base 12 and water exits therethrough as required. The exiting water may or may not have been circulated across the fins 14. Indeed, in such a configuration, some of the water may enter, its temperature may approach its vaporization temperature, and yet remain swirling in the corners or along the edges of the base without being replaced by fresher, cooler water that will absorb more of the heat. Additionally, some of the fresher, cooler water entering through the input port may quickly exit through the output port without absorbing much heat at all. Thus, another deficiency of the prior art water cooled thermal apparatuses is the poor and inefficient circulation of water therethrough.
Therefore, despite the benefits of such water cooled thermal apparatuses, they have heretofore had limited utility in small electronic devices due to the very little extra space within the cases or housings of such devices. Considering the increasing pressure to miniaturize the electronic devices, manufacturers of such devices must find alternative means for cooling heat generating components unable to adequately dissipate heat on their own. Given the widespread use of smaller electronic devices such as PDA's, cell phones, laptop computers, etc., as well as the increasing need to enhance the capabilities of such devices, manufacturers will soon need to provide cooling systems for these smaller devices that are efficient, small, inexpensive, and reliable.
Therefore, there exists a need in the art for an effective cooling apparatus that may be used in small electronic devices. Additionally, there is a need in the art for a cooling apparatus that may be fitted into small openings or crevices within a computer and fastened to a heat generating component in order to effectively dissipate heat from the component. There is a need in the art for an inexpensive cooling apparatus that is able to effectively circulate liquid to quickly and efficiently remove heat from a heat generating component. Finally, there is a need in the art for a cooling apparatus that effectively cycles fluid therethrough to ensure that the fluid absorbs as much heat as possible before exiting the apparatus.